Gas turbines are widely used in industrial and power generation operations. A gas turbine generally includes, in serial flow order, a compressor, a combustion section and a turbine. The combustion section may include multiple combustors annularly arranged around an outer casing. In operation, a working fluid such as ambient air is progressively compressed as it flows through the compressor. A portion of the compressed working fluid is routed from the compressor to each of the combustors where it is mixed with a fuel and burned in a combustion chamber or zone to produce combustion gases. The combustion gases are routed through the turbine along a hot gas path where thermal and/or kinetic energy is extracted from the combustion gases via turbine rotors blades coupled to a rotor shaft, thus causing the rotor shaft to rotate and produce work and/or thrust.
Particular combustion systems utilize bundled tube type fuel nozzle assemblies for premixing a gaseous fuel with the compressed air upstream from the combustion zone. In certain combustor operating modes such as during diffusion flame operation, it may be desirable and/or necessary to have the capability to premix a liquid fuel with the compressed air upstream from the combustion zone via the bundled tube fuel nozzle assembly.